Modeling Thermal Dust Emission with Two Components: Application to the Planck High Frequency Instrument Maps

January 16, 2015
Figure 8

Figure 8. One degree FWHM full-sky map of f1 derived from our low-resolution fits described in Section 7.4. [from A.M. Meisner and D.P. Finkbeiner, "Modeling thermal dust emission with two components: application to the Planck high frequency instrument maps," 2015 ApJ 798:88 | doi:10.1088/0004-637X/798/2/88. © 2015 The American Astronomical Society.]

Graduate student Aaron Meisner and Prof. Douglas Finkbeiner have recently published a paper in The Astrophysical Journal, "Modeling thermal dust emission with two components: application to the Planck high frequency instrument maps " (ApJ 798: 88). Abstract is below:

We apply the Finkbeiner et al. two-component thermal dust emission model to the Planck High Frequency Instrument maps. This parameterization of the far-infrared dust spectrum as the sum of two modified blackbodies (MBBs) serves as an important alternative to the commonly adopted single-MBB dust emission model. Analyzing the joint Planck/DIRBE dust spectrum, we show that two-component models provide a better fit to the 100–3000 GHz emission than do single-MBB models, though by a lesser margin than found by Finkbeiner et al. based on FIRAS and DIRBE. We also derive full-sky 6farcm1 resolution maps of dust optical depth and temperature by fitting the two-component model to Planck 217–857 GHz along with DIRBE/IRAS 100 μm data. Because our two-component model matches the dust spectrum near its peak, accounts for the spectrum's flattening at millimeter wavelengths, and specifies dust temperature at 6farcm1 FWHM, our model provides reliable, high-resolution thermal dust emission foreground predictions from 100 to 3000 GHz. We find that, in diffuse sky regions, our two-component 100–217 GHz predictions are on average accurate to within 2.2%, while extrapolating the Planck Collaboration et al. single-MBB model systematically underpredicts emission by 18.8% at 100 GHz, 12.6% at 143 GHz, and 7.9% at 217 GHz. We calibrate our two-component optical depth to reddening, and compare with reddening estimates based on stellar spectra. We find the dominant systematic problems in our temperature/reddening maps to be zodiacal light on large angular scales and the cosmic infrared background anisotropy on small angular scales.